3RV1021 Motor Starter Protectors (MSP’s) are built for a world of applications while meeting the requirements of control users worldwide. Each MSP features a manual ON/OFF switch, a Class 10 adjustable bimetallic overload relay and magnetic trip elements for short circuit protection.

3RV1021 motor starter protectors are equipped with bimetallicbased, inverse-time delayed overload releases - electromagnetic short-circuit releases. The overload releases can be set in accordance with the load current. The overcurrent releases are permanently set to a value 13 times the rated current and thus enable trouble-free start-up of motors.

S00 3RV1011 MSP'S are actuated via a rocker operating mechanism and S0 3RV1021 MSP's via a rotary operating mechanism. If the MSP trips, the rotary operating mechanism switches to the tripped position to indicate this. Before the MSP is reclosed, the rotary operating mechanism must be reset manually to 0 position, in order to prevent the former from closing by mistake before the fault has been cleared.